Local responders and crews from CSX Corp. were working Wednesday to determine how much of the liquid spilled in Willard, about 65 miles southwest of Cleveland.

A CSX spokesman says four cars derailed at the yard late Tuesday while switching trains. He says the car that leaked was carrying about 26,000 gallons of styrene monomer, which is used to make various plastic and rubber products.

City Manager Brian Humphress tells The Sandusky Register that liquid leaked from a 4-inch hole for several hours before it was resealed.

Residents were told overnight to evacuate an area encompassing an estimated 400 homes.